1. Technical Field
The present invention relates to an ink composition, an ink cartridge, an inkjet recording device, and an inkjet printed matter.
2. Background Art
Inkjet printers are significantly diffusing due to their advantages such as low noise and low running costs, and many printers capable of printing color images on plain paper have been actively introduced into the market.
However, it is extremely difficult to satisfy all the properties required of images such as color reproducibility, abrasion resistance, durability, light resistance, drying property, feathering, color bleed, duplex printing, and ink discharging stability. As a result, the ink used is selected based on the prioritized particular application.
In general, the ink for use in inkjet recording is mainly composed of water, with a coloring agent (colorant) and a hydrosoluble solvent such as glycerin to prevent clogging.
As the colorant, dyes are widely used for their excellent coloring and stability. However, the light resistance and water resistance of images are insufficient.
Water resistance is improved to some degree by using special recording media for inkjet having an ink absorbing layer, but is not satisfactory when it comes to plain paper.
To compensate for such defects, ink using a pigment has begun to be used as a coloring agent.
Although pigment ink is successful and superior to dye ink with regard to light resistance, water resistance, etc., the coloring of pigment ink is degraded by coherence of beams of light having different wavelengths and phases produced by multiple reflections of the beams of light within the pigment. For this reason, pigment ink is considered to be inferior to dye ink in general with regard to coloring.
In an attempt to compensate for such degradation of the coloring of pigment ink, pigment particulates that are coated with a resin are used.
According to this method, the fixing property and the gas resistance of pigment ink are further improved by the resin, and in addition dispersion is greatly stabilized. However, currently, pigment ink is not still on a par with dye ink with regard to gloss.